I think we can all agree that we know what happiness is and when we and or our friends are happy, but can happiness be measured for whole countries? And when we talk about happiness for a whole population, just what are we talking about.
For individuals., important things like being in a stable and loving relationship, having a secure and fulfilling job, being secure in the fact that if you get sick or have an accident that you will be able to afford proper care all come to mind. Other factors include access to education, freedom of activities, a comfortable retirement, and importantly protection from violence and even political coercion.
A number of organizations from the United Nations to the Gallup poll, using survey and economic data come to the same conclusions: Scandinavia wins every time, Canada beats the USA which is in about the middle in happiness, and at the bottom despotic, and especially war-torn countries.
Factors which gather all this input into a simple number are the Gini indices for wealth and income, especially income. The Gini index is a way to put a number, between 0 and 1, on the distribution of some asset. It is usually applied as noted to wealth or income but can be applied other things. If something, wealth for instance, is held by very few or even one and nobody else has any then the index would be at or near 1. On the other hand, if it is evenly distributed throughout the population, then the value would be near 0.
Back to happiness. It should be obvious that the happiest countries all favor socialism in the broadest meaning of the word. Economic systems in countries are organized somewhere between capitalism and socialism, although neither exist in the purest form anywhere in the world.
Even in capitalistic United States we have socialism in the form of social security, medicare and medicaid, and even more mundane structures such as police and fire protection. Rigidly socialist North Korea has some capitalism by way of street vendors who sell things like food and cheap commodities.
The strongest objection by capitalists to socialism is that it throttles innovation. Why work hard or try to create wealth when the government just takes so much in taxes? The happiest people live in the Scandinavian countries which are all are relatively socialistic. They also have relatively high gini (wealth) indices. The people of Denmark, frequently ranked as the happiest, has a gini index comparable to the United States.
Where we and the countries with the happiest people vary is the gini index for income. Income is much more evenly dispersed in the happy countries. This is net income which includes not only cash payments for work but also the social welfare network which provides healthcare, education, retirement, a host of other services which enrich life.
The happiest people in the world live in countries that have low gini indices for income but relatively high indices for wealth. This means that the largest number of people have sufficient income to ensure that they don’t have to worry, while at the same time allowing wealth to accumulate to those who seek it.